Pneumatic-carrier check



July lzo, 1926. A

J. J'. s'roE'rzEL PNEUMATIC CARRIER CHECK Original Filed Mayy 23, 1924 Patented July 20, 1926.

UNITED STATES PATE JOSEPH J'. STOETZEL, OF BELLAIRE, NEV YORK, ASSIGNOR TO G. & G. ATLAS SYSTEMS,

INC., A CORPORATION OF NEW YORK;

PNEUMATIC-CARRIER CHECK.

Application filed May 23, 1924, Serial No. 715,301. Renewed January 16, 1926.

It often happens, in the construction of a pneumatic despatch tube system, that it is desirable to provide for a sheer drop, or

nearly vertical slide, at some place in the lSystem of tubing. It is well known that in large systems, the transit tubes assume many angles of travel, upward, downward, as well as level. And it is also well known that the atmospheric pressure behind they `carrier remains substantially the same while the exhauster is creating the maximum, or

carrier driving, iow. When, therefore, a

carrier takes a sudden drop or plunge downward the accrued momentum of the carrier is added to the speed derived from the driving atmosphere, and converted into increased flight by reason otgravity of the carrier. At such times it becomes desirable to check the speed of the falling carrier for -obvious reasons.

The object of my invention is to provide a simple and eliective checking device, op-V erated pneumatically by the increased airpressure itself, to counteract the tendency oit' the carrier to acquire a dangerously increased speed. And to make this checking device such that it is always ready to act upon the emergency call, although normally idle.

To this end my invention consists, broadly, in a pneumatic carrier check, located in, or communicating with, a, transit tube of a pneumatic despatch tube system, especially where a sharp drop or steep declivity exists, and comprising a movable plate blade, or other partly-damming device, adapted to choke to a desired vextent the passage of air preceding a carrier, when tending to move too rapidly,-and a diaphragm-valve, or equivalent device, adapted to be operated by the increased pressure incident to the too rapid movement of the carrier, and thus bring said choking device into action.

As a preferred form of my improved checking device I have shown, in the accompanying drawing, a pneumatic carrier check involving my invention,the damming device being shown as a thin plate hanging inside a transit tube ot a pneu-- matic despatch tube apparatus,-a casing secured to the outside of said tube and communicating with the interior of said tube by suitable ports,and a diaphragm valve for operating said damming device,-the diaphragm chamber being a part of said casing but with one side of the diaphragm always open to the atmosphere.

In this drawing Fig. l is a diagrammatic sketch oa por-I tion of a pneumatic despatch tube system of the open current type, without any attempt to show proportions or any details except vto illustrate the fact that my improved carrier check is to be interposed in ysuch a system, near the heel of a drop, and between the open bell-mouth (not shown) and the dischargeoutlet,-which discharge-outlet is, naturally above the control-valve, and the eXhauster. y

Fig. 2 is a vertical section' on a larger scale of my improved pneumatic carrier check.

Fig. 3 is a horizontal section on line 8 3 of Figure 2.

Same letters indicate similar parts in the different figures.

A, represents a carrier as descending in a transit tube ofra pneumatic despatch tube system not shown above the break. B, is the transit tube which continues to the dis charge outlet C, after which it becomes the exhaust tube D. E is a valve-casing enclosing any suitable air-controlvalve, and F, is the exhaust drum which `here stands for the usual eXhauster, including motor and governor.

All these details are of usual and suitable construction and should, therefore, be readily understood without further explanation.

G, in Figure 1, stands generally for my improved carrier check, which, however, is there shown only diagrammatically. The detailed construction is shown in Figures 2 and 3.

H, is a casing of suitable form to secure an air-tight communication between the interior of the transit tube B, and the diaphragm valve I, upon the action of which depends the movement of the plate K. L, is a flexible diaphragm which, though shown in Figure 2 as extended, is normally collapsed into the casing H, by reason of the fact that the outer side of the diaphragm is always exposed to the atmospheric pressure and it is only when the air-pressure inside the casingy (and Vthe transit tube ahead of the carrier) exceeds atmospheric pressure that the diaphragm bulges outwardly as shown.

At the centre of this diaphragm is a .plate or disc M, to which is fastened a link N,

the other end oi wliich is pivoted in a yokeV O. T his yoke is mounted on the outer end ot the choking device K, which vswiiigs-on the hinge P, in the port Q through which air-communication is had between the cas'- ing H, and the inside of the' tube B, by the small holes R, R.

The operation oic my improved carrier check is as follows Before a carrier in transit reaches the portion of the transit tube in' which occurs the drop or descent wherein the carrier check is located, said check, so tar as the plate or damming device is concerned, is'idle, the plate hanging iii a downward direction as shown in dotted lines close to the inner wall oit' the transit tube, and the diaphragm collapsed. As soon as a carrier drops or descends too rapidly for safety or for desired operation of the system, the air ahead of the carrier Ybanks up, creating a temporary pressure greater than atmospheric. Some oi Vthis over-pressure air'passes through the holes R, R, into the casing H, back'otl the collapsed diaphragm L, and forces the diaphragm outwardly into the extended position shown iu Figure 2. This action mechanically pulls the yoke O, and with it the plate K, from the position shown in dotted lines'into that shown in full lines, witlithe result that the lower portion oit said plate swings upwardly` insidethe transit tube and partly cuts off the liow of air. The air thus held back by the partial closing ofthe plate K, increases `the density of` theV air between. said plate and the approaching carrier` and acts as a tion and tliecarrier is free to move quietlyv to the discharge outlet C.

The uses andv advantages of inyinventioii will, I think, be readily understood without Jfurther explanation.

I claimz- 1.-. A pneumatic carrier check which comprises a current-clicking device, adapted to interpose itself in the path ot' an approachingV carrier andthereby form a retarding cushion of air between said carrier and said device to diminish thespeed o'said-carrier', and pneumatic means set iii actionA by the increasing density oit the an" ahead of said carrier to causeA said clicking device so to F interpose.

21In a pneumatic tube systemf, a device tor checking excessive speed of carriers and means responsive to the increase in pressure within the system produced by theexcessive speed of-acarrier,gi'or rendering said check` ing device' eiiective.

3. In a pneumatic tube system, a device adapted, when Vrendered',eiiective, to cause the formation of a retarding cushion of a-ir inl advance'of acarrier passing through the system, and pneumatic means responsiveV to a change of pressure conditions within the system resulting from the excessive speed of a. carrier, for rendering said device eti'ectivei JOSEPH J. STOETZEL 

